1. Field of the Invention
The present invention relates to a pen-type input device used in a computer system for causing a cursor to move on a display surface and entering data about graphic patterns and characters into a computer.
2. Description of the Prior Art
Conventional input devices for use with computers include a keyboard, a mouse, a digitizer, a light-pen, a tablet, etc. Among these input devices, the mouse is a device that can be moved on the surface of a tablet or the like, causing a cursor to move to a corresponding point on the screen of a cathode ray tube (CRT). The mouse is capable of moving the cursor at high speeds by a relatively simple manual operation and is able to create graphic patterns, marks or characters freely on the display surface. The mouse is divided broadly into two categories by the system used for the detection of the amount of movement of the mouse. The mouse falling in the first category has a ball rotatable in response to the movement of the mouse for detecting the amount of movement of the mouse, while the mouse in the second category includes a photosensor for detecting the amount of movement of the mouse while the mouse is being moved on a flat surface provided with a grid or network of evenly spaced horizontal and vertical lines.
The mouse can be used in various manners depending on the software used to control the operations of a computer system. When used in computer graphics for creating a mark or a free curve on the display surface, the mouse is moved in such a direction that a cursor is moved in a desired direction.
However, due to its size and construction, the mouse cannot be moved finely. In addition, a direct monitoring of the movement of the mouse is not possible. It is, therefore, almost impossible for the mouse to perform an appropriate input of data on a fine figure or character into a computer.